Re: Looking for advice about using NM with a Sprint U301 modem

[Daenyth Blank <daenyth gmail com>]

On Wed, Jun 2, 2010 at 03:16, Dan Williams <dcbw redhat com> wrote:
> On Thu, 2010-05-27 at 12:04 -0400, Daenyth Blank wrote:
>> Hi all,
>>
>> I'm trying to find out some information regarding the Sprint U301 3G
>> modem. Our use case for it is that it will be attached to an embedded
>> machine running ubuntu with networkmanager, in addition to our
>> software. I've been trying to get this modem to connect reliably and
>> am having some issues with it. I've added a udev rule so that the
>> usbserial driver is given the correct vendor/product information, and
>> it connects automatically on boot, but not reliably. Some boots it
>> does not connect at all and won't until I reboot. Sometimes it
>> disconnects while the machine is running. If it disconnects either by
>> itself or from deactivating the connection, it will not connect again
>> and needs a reboot. The nm/mm logs say that serial requests are timing
>> out when it's in the non-connected state. I haven't been able to
>> recover from the disconnected state with anything about a reboot.
>>
>> Is there anything we can do with this device to increase reliability?
>> Failing that, can you recommend a usb Sprint 3G modem that will be
>> more reliable? If there are none, do you have any recommendations for
>> any brand of 3G modem that will work well in this situation? The boxes
>> will be deployed where manual access is not easy, so it needs to be
>> able to connect and recover from disconnections automatically, or at
>> least in a way that can be scripted easily.
>
> You're certainly not going to be able to get the WiMAX part of the
> device working automatically since we dont' have drivers for the Beceem
> chipset of the WiMAX side.  However, the EVDO side should work with
> cdc-acm, so if you have to use 'usb-serial' there's already something
> wrong.
>
> I suspect you need to use usb_modeswitch to eject the fake CD that the
> device provides too, correct?
>
> Honestly, UTStarcom-based devices (which the 300 and 301 are rebrands
> of) often don't work that well as you've found out.  I'd recommend a
> Sierra device instead, as Sierra is also very active in Linux kernel
> development and has great support for their devices.
>
> Dan
>
>

Thanks Forest, Dan. I'm going to recommend to our client that we use
the Sierra cards. Appreciate the advice!